Method of shaping filament supports of a miniature signal lamp

ABSTRACT

A process and an apparatus for manufacturing a miniature signal lamp. The lamp has a base having a longitudinal axis and radially projecting filament supports that project from the base and lie in substantially a common plane. The end portions of each filament support furthest from the base are connected to the filament. A portion of each filament support is formed into a Vshaped configuration lying in a plane substantially perpendicular to the common plane wherein alternate ones of said V-shaped portions point in one longitudinal direction and the remaining ones point in the opposite longitudinal direction.

United States Patent 11 1 1111 3,837,371 Rochet Sept. 24,1974

[ METHOD OF SHAPING FILAMENT 3,172,432 3/1965 Foreign Application Priority Data Feb. 29, 1972 1 France 72.06850 US. Cl. l40/71.5, 29/25.]8 Int. Cl B2lf 45/00 Field ofSearch 29/2513, 25.15, 25.18;

References Cited UNITED STATES PATENTS Flauss, Jr. et al l40/7l.6

Hawkey et al. l40/7l.6

Primary Examiner-Roy Lake Assistant Examiner-James W. Davie Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato; Bruce L. Adams [5 7] ABSTRACT A process and an apparatus for manufacturing a miniature signal lamp. The lamp has a base having a longitudinal axis and radially projecting filament supports that project from the base and lie in substantially a common plane. The end portions of each filament support furthest from the base are connected to the filament. A portion of each filament support is formed into a V-shaped configuration lying in a plane substantially perpendicular to the common plane wherein alternate ones of said V-shaped portions point in one longitudinal direction and the remaining ones point in the opposite longitudinal direction.

7 Claims, 10 Drawing Figures METHOD OF SHAPING FILAMENT SUPPORTS OF A MINIATURE SIGNAL LAMP This invention relates to a miniature signal lamp with base, and to the process for its manufacture and the devices for the said manufacturing process.

Already known are miniature lamps of very small diameter less than 14 mm, these lamps functioning under standard voltages of 48, 60, 130 V and above. Some of these lamps are at present manufactured manually, starting with the base, by manual fitting of a filament holder formed by a number of hook-supports, made of molybdenum, in principle with an odd number of these, from three to eleven hooks arranged radially. After the free ends of each filamentary support have been wound round the conducting filament of the lamp, the supports are folded back manually in a non-uniform manner, in such a way that on the one hand a quasi-perfect conductor voltage is obtained and on the other hand the maximum final overall diameter of the lamp is reduced to a minimum; in spite of this operation, the diameter remains around 14 mm.

The purpose of this invention is to eliminate this disadvantage, and it therefore provides a new miniature lamp of this type particularly suitable for automatic mass production in large runs, and which above all has the advantage of having a final mounting diameter considerably smaller than the diameter of lamps known today since it is reduced to a value of around 8 mm.

To achieve this, this miniature signal lamp with base, having a filament connected to power supply wires lodged in the base and secured by a number of radial filamentary supports, each of the latter having a first end fixed into a central bead of the base, and its other free end folded over on itself, to form a loop through which the filament passes, is characterised in that the various filamentary supports are folded into V-shapes open alternately towards the top and towards the bottom around the base of the lamp.

The miniature lamp in conformity with the invention thus offers the advantage that due to the mechanical folding into V-folds of the filamentary supports, its overall diameter is considerably reduced and can be reduced as required to a maximum mm for the finished lamp. Furthermore, due to the alternating opening towards the top and towards the bottom of the successive folds formed by the filamentary supports, the filament follows a zig-zag path and is thus perfectly tensioned. Finally the lamp in conformity with the invention is particularly suitable for automated production.

The invention also relates to a process for manufacturing base-mounted miniature signal lamps commencing with a base fitted with radial filamentary supports lodged at one of their ends in a central glass bead mounted at the top of the base, the ends of the filamentary supports being wound to form loops in which the filament is held in position, characterised in that each filamentary support is folded to a V-shape, at a point roughly in its middle, and alternately towards the top and towards the bottom for the various supports arranged in a star shape around the central bead.

An embodiment of this invention is described below, by way of example only, with reference to the annexed drawings, of which:

FIG. 1 shows a schematic vertical projection of a miniature lamp base as it appears before the first stage in the process of manufacturing the lamp, i.e., with head downwards.

2 FIG. 2 shows the lamp base of FIG. 1 along line 11.

FIG. 3 shows an identical schematic vertical projection of the base after winding of the free ends of the filamentary supports around the filament.

FIG. 4 shows an identical schematic vertical projection of the base after shaping of the V-folds in the centres of the filamentary supports.

FIG. 5 shows an identical schematic vertical projection of the base after a further shaping operation on the supports which brings the V-folds closer to the axis.

FIG. 6 shows a view from above of the punch which produces the V-folds on the supports alternately towards the top and towards the bottom.

FIG. 7 shows a vertical projection of the punch shown in FIG. 6.

FIG. 8 shows a vertical projection of the bottom matrix corresponding to the punch shown in FIG. 7.

FIGS. 9 and l0 show respectively a vertical projection and a view from above of the device by means of which the V-folds of the filamentary supports are brought closer to the axis of the lamp base.

Base 1 of the miniature signal lamp shown in FIG. 1, as it appears before the first manufacturing operation, comprises a body 2 ending at the top in a nipped section 3 and at its bottom in a flared rib 4. Base 1 is extended at its bottom towards a vacuum unit 5. In base 1 are embedded two electrodes or conductors 6 and 7, for the power supply to filament 8 connected at their top ends which project above nipped section 3. Filament 8 is shown not yet mounted in FIG. 1.

At its top end, base 1 has a central glass bead 9 into which are fixed the ends of the radial filamentary supports 10, only two of which are shown in FIG. 1. These molybdenum supports are of a number varying between 3 and 11 for example, and are generally of an odd number. For the views from above of the lamp and its manufacturing devices, FIGS. 2,6 and 10, the number selected for the supports is the traditional number of 7 arranged in a star pattern around the central bead 9. The overall diameter a between the external ends of the two opposite filamentary supports 10 is around 20 mm before any manipulation of the said supports.

As was shown in FIG. 2, filament 8 is rested on each free end of supports 10, after the loop of the said filament has been closed to permit subsequent flow of electric current. The first stage in the manufacturing process for the signal lamp is that of winding or hooking, in the traditional way, the free ends 10a of filamentary supports 10 to form loops or pigs tails" 11, around filament 8. The base of the lamp then appears, after this operation, as it is shown in FIG. 3, i.e., with its filament 8 held in position by loops 11.

The next stage follows on the basis of the original manufacturing process and consists of folding each filamentary support 10 roughly at its centre into V-folds, opening alternately towards the top and towards the bottom for the various supports. We thus obtain a base as shown in FIG. 4 in which can be seen on the lefthand side a V-fold 12 with its point towards the bottom, formed from left-hand support 10, and another V-fold 13 with its point towards the top, formed from the opposite filamentary support. This operation is carried out very easily byusing a bottom matrix 14 (FIG. 8) and a corresponding top punch 15 (FIGS. 6 and 7). Matrix 14 has a central axial recess 16 into which bead 9 is inserted and along the front surface 17 of the said matrix there are radial grooves into which are seated the various filamentary supports the ends of which have been previously looped. This matrix 14 is oper ated with a top punch 15 with axial movement 18, the punch having on its bottom horizontal surface 19 ribs complementary to the grooves in the matrix; the ribs are distributed around the axis of the punch and offer successive peaks 20 and hollows 21 engaging respectively with complementary hollows 22a and peaks 22, of the same shape, provided in the grooves to form, from the filamentary supports 10 seated in these grooves, V-folds opening alternately towards the top and towards the bottom. Advantageously each peak 20 of the punch and 22 of the matrix has a recess 23 for loop 11 of support 10. The punch 15 furthermore has an axial recess 24 over its entire height to permit penetration by the lamp base.

Folding into V-folds alternately towards the top and towards the bottom of supports 10, obtained either by downwards movement 18 of the punch, or by the upwards movement 25 of the matrix, or by a combination of these two movements, has the effect:

of tensioning the filament of reducing the mounting diameter of the lamp as can be clearly seen in FIG. 4.

Before completing this shaping of the filamentary supports 10 and above all before further reducing lamp diameter, deformation of the filamentary supports 10 is accentuated by exerting on folds l2 and 13 thrusts directed towards the axis of lamp base 1, in the direction shown by arrows fl and f2 in FIG. 5. As a result, the V-fold 12 is shifted further towards the bottom and towards the axis of the base whilst conversely the opposite fold 13 is pushed further towards the top and towards the axis. The tension of filament 8 is further improved by this operation.

Folding into a V-shape of the filamentary support and its supplementary deformation permit a considerable reduction in the diameter of the lamp once mounted, a diameter which attains a maximum of 8 mm. All the folding operations of the filamentary supports 10 can be carried out very easily on known types of automatic mounting machines.

The second supplementary shaping operation on supports 10 can be carried out by means of the device shown in FIGS. 9 and 10 by way of example. This device consists of an essentially cylindrical body 26 comprising a center chamber 27. Lamp base 1 is shown schematically at the top section of body 26 with its filaments 10 already folded at their centres. On upwards movement of a cylindrical control cam 28 with a tapered head, pistons 29, mounted to slide in body 26, retreat and cause a rotational movement of levers 30 around their respective axes 31, with engagement with two parallel wings 32a and 32b ofajaw 32. Each lever 30 oscillates on a vertical plane and produces at its top end a movement of adjusting pushbutton 33 facing the axis of body 26. The pushbutton 33, screwed onto the top part of lever 30 and adjustable in position by means of its hexagonal head 33a and its lock nut 34, is in contact with the rear surface of a radial finger 35, which presses the ends of supports 10 towards the axis of the lamp base. Advantageously the front surface 36 of finger in contact with support 10 comprises a vertical groove ensuring perfect holding of the said filament and holding it in position during its return movement.

After supplementary deformation of each filamentary support the cam 28 is lowered again and each finger 35 is retracted by means of a spring-blade 27, and by its final movement the finger makes lever 30 pivot in the opposite direction, which has the effect of returning piston 29, disengaged from the inclined surface 28a of the cam, towards the centre of body 26. The fingers 35 can be mounted so as to slide in body 26, or in another version can be mounted between the top surface 26a of the body and a circular flange 37 screwed at 38 on the latter.

As a simplification of the latter device, we have arranged on an identical vertical plane a piston 29, a lever 30, an adjustable pushbutton 33 and a finger 35, each of these units operating on a single support 10, but all other versions apart from the star-arrangement of the 7 distinct units form an integral part of the framework of this invention. The same applies to all conceivable variations in the number of supports 10, the shape and position of each V-fold, and the device (matrix and punch) permitting the folding of the latter.

I claim:

1. Process for manufacturing a base-mounted miniature signal lamp comprising the steps of: providing a base fitted with radial filamentary supports fixed at one of their ends into a central glass bead, fitted at the top of the base, the ends of the filamentary supports being wound to form loops in which the lamp filament is held in position; and folding each filamentary support to a V-shape, roughly in its center, and alternately towards the bottom and towards the top, in the case of the various supports arranged in a star-pattern around the central bead, so as to tension the filament held at the end of each support by giving it a zig-zag path.

2. Manufacturing process for a signal lamp according to claim 1, further comprising the step of applying thrusts on the V-folds formed by the filamentary supports towards the axis of the base, the thrusts exerted on the V-folds pointing towards the bottom being slightly inclined towards the bottom, while the thrusts exerted on the V-folds pointing towards the top are slightly inclined towards the top, so as to bring the V- folds closer to the axis.

3. A process for manufacturing a lamp comprising the steps of: providing a base having a longitudinal axis and radially projecting filament supports projecting therefrom and lying in substantially a common plane and connected to a filament at one end portion thereof furthest from said longitudinal axis; and forming a portion of each filament support including said one end portion thereof into a V-shaped configuration lying in a plane substantially perpendicular to said common plane and wherein alternate ones of said V-shaped portions point in one longitudinal direction and the remaining ones point in the opposite longitudinal direction.

4. A process according to claim 3, wherein said common plane is substantially perpendicular to said longitudinal axis.

5. A process according to claim 4, wherein said common plane passes through said longitudinal axis at a point between the two end portions of the base.

6. A process according to claim 3, further comprising the step of reducing the radially projecting distance of the support members by bending each support member towards said longitudinal axis thereby decreasing the angle of the vertex of the V-shaped portions thereof.

7. A process according to claim 3, wherein the vertex of each V-shaped portion is approximately at the center of each filament support member. 

1. Process for manufacturing a base-mounted miniature signal lamp comprising the steps of: providing a base fitted with radial filamentary supports fixed at one of their ends into a central glass bead, fitted at the top of the base, the ends of the filamentary supports being wound to form loops in which the lamp filament is held in position; and folding each filamentary support to a V-shape, roughly in its center, and alternately towards the bottom and towards the top, in the case of the various supports arranged in a star-pattern around the central bead, so as to tension the filament held at the end of each support by giving it a zig-zag path.
 2. Manufacturing process for a signal lamp according to claim 1, further comprising the step of applying thrusts on the V-folds formed by the filamentary supports towards the axis of the base, the thrusts exerted on the V-folds pointing towards the bottom being slightly inclined towards the bottom, while the thrusts exerted on the V-folds pointing towards the top are slightly inclined towards the top, so as to bring the V-folds closer to the axis.
 3. A process for manufacturing a lamp comprising the steps of: providing a base having a longitudinal axis and radially projecting filament supports projecting therefrom and lying in substantially a common plane and connected to a filament at one end portion thereof furthest from said longitudinal axis; and forming a portion of each filament support including said one end portion thereof into a V-shaped configuration lying in a plane substantially perpendicular to said common plane and wherein alternate ones of said V-shaped portions point in one longitudinal direction and the remaining ones point in the opposite longitudinal direction.
 4. A process according to claim 3, wherein said common plane is substantially perpendicular to said longitudinal axis.
 5. A process according to claim 4, wherein said common plane passes through said longitudinal axis at a point between the two end portions of the base.
 6. A process according to claim 3, further comprising the step of reducing the radially projecting distance of the support members by bending each support member towards said longitudinal axis thereby decreasing the angle of the vertex of the V-shaped portions thereof.
 7. A process according to claim 3, wherein the vertex of each V-shaped portion is approximately at the center of each filament support member. 